When comparing Dispatch vs Seed, the Slant community recommends Dispatch for most people. In the question“What are the best e-mail clients for iOS?”Dispatch is ranked 3rd while Seed is ranked 15th. The most important reason people chose Dispatch is:

Integrates with a wide variety of other services

Dispatch will scan your e-mail for dates and times, phone numbers and e-mail addresses, real-world locations/addresses, web links, etc. and offer taking action with one of the aforementioned apps.

Pro

Supports TextExpander touch snippet expansion

TextExpander is a text macro tool that can, among other things, autofill your adress, signature, etc. It does that with a feature called 'snippets' and Dispatch has that functionality built in so you can respond to your e-mails quicker.

Pro

Quick actions on swipe

A short swipe off the message will bring up a menu with 5 options of interacting with the message: mark it read, star/flag it, archive it, move it to a folder of choice, or delete it.

A longer swipe will initiate a user-configured "quick action" such as archiving or marking the message as junk.

Pro

Automatic salutation

When you're replying to a message, Dispatch will check the sender name and automatically start the message with Hi Name,. You can choose to turn it off completely or configure to take place only in certain situations.

Pro

Background refresh

Dispatch will download mail in the background so you don't have to wait for it to update when you open your app.

Pro

Clean design

The design of dispatch is minimalistic and intuitive if you've ever used gestures. An uncommon design choice includes focusing on the body of the text when choosing to compose a message and filling out the subject and who to send the message to later.

Pro

Includes calendar information for added accounts

For each account added to the application Seed will attempt to pull associated calendars into the app as well allowing you to manage both mail and calendar events from one application.